I voted for Emma based on flow. I also love the name Emma. It's a bit popular I know but it's classic so it should never become dated. Willow and Harper are also nice and have good flow but on their own they don't match up to Emma (in my opinion). I love the name Scarlett and if it's your number 1 name I say for it. The alliteration might put me off a little if it were my own child, but on the other hand it might be cute! Have you ever considered Charlotte? Again, popular I know.. but it's similar to Scarlett in sound and style, without the double"Sc" issue! CharlotteChristinaScott.. just a thought

I voted for Aria! Both my first and middle name end in an "ah" sound and I love it. It flows nicely and imo it sounds elegant. I love Aria to begin with, but paired up with Christina, I like it even more. AriaChristina sounds memorable and lovely. I wouldn't worry about the pronunciation issues with Aria, I think people over estimate how problematic it can be.

I voted for WillowChristinaScott and would have vote for Aria second. I think with such a first-namey last name and a beautiful and classic middle like Christina you can afford to go a little out of the box and whimsical. I think WillowScott would be beautiful. (I prefer Willow over Aria because Scott is short and AriaScott in just a very short name without the Christina. For me it feels like a few letters are missing to round out the flow of the name).